The conventional Venetian blind consists of a slat-lifting mechanism having an outer pull cord, a slat set pull cord and a ratchet member. The outer pull cord is so exposed as to facilitate the pulling of the outer pull cord by hand. The slat set pull cord is connected with the slat set and linked with the outer pull cord for controlling the ascending and the descending of the slat set. In the meantime, the ratchet member is driven by the slat set pull cord to remain in an engaging state or a disengaging state, so as to locate the slat set at a desired position.
The exposed outer pull cord of the slat-lifting mechanism of the prior art is a potential safety hazard in view of the fact that a playful child may be accidentally strangled by the exposed outer pull cord. In addition, the exposed outer pull cord is prone to becoming entangled with the slat set.